Answer:
5 mg
Explanation:
If one half life is 4 hours, then 3 half lives is 12 hours.
This means that the sample will decay to 1/8 of its original amount.
So, the answer is 40(1/8) = 5 mg.
A balloon contains 10.0 g of helium gas. If the initial volume is V, and the temperature
and pressure are held constant, what is the final volume (in terms of V) after 10.0 g
of neon is added?
Answer:
1.2 V
Explanation:
10 g helium = 2.5 moles He
10 g Neon = ~ .5 mole neon
2.5 is to V as (2.5 + .5) is to x
2.5 / V = 3/x
2.5 x = 3 V
x = 3/2.5 V = 1 1/5 V
Avogadro's Law (P,T constant)
[tex]\tt \dfrac{V_1}{n_1}=\dfrac{V_2}{n_2}[/tex]
n = mol
V = volume
AM He = 4 u, mol = 10 : 4 = 2.5
AM Ne = 20 u, mol = 10 : 20 = 0.5
[tex]\tt \dfrac{V}{2.5}=\dfrac{V_2}{2.5+0.5}\\\\V_2=\boxed{\bold{1.2V}}[/tex]
How many moles are present
in 3.25 x 1024 atoms P?
Answer:
5.40 moles ( to 3 signif digits )
Explanation:
ONE mole is Avagadro's Number 6.022 x 10^23 atoms/mole
3.25 x 10^24 atoms / (6.022 x10^23 atoms/mole ) = 5.396 moles ~ 5.40 moles
Determine the empirical formula of a compound containing 47.37 grams of carbon, 10.59 grams of hydrogen, and 42.04 grams of oxygen. In an experiment, the molar mass of the compound was determined to be 228.276 g/mol. What is the molecular formula of the compound
The molecular formula is C9H24O6
Given the Mass of C = 47.37g ,Mass of H = 10.59g and Mass of O = 42.04g
The total mass of these elements is 100g, taking a proportion of their molar masses.
C = 47.37/12= 3.95
H = 10.59/1 = 10.59
O = 42.04/16= 2.63.
Dividing with the smallest proportion which is 2.63
C=3.95/2.63 = 1.5
H =10.59/2.63 =4
O = 2.63/2.63= 1
Multiplying by 2 to get a whole number.
C = 1.5x2 = 3
H= 4x2 = 8
O = 1x2= 2
The empirical formula is C3H6O2
(Empirical formula)n= molecular mass
(C3H8O2)n =228.276
(12x3 +8+16x2)n= 228.276
76n = 228.276
n = 228.276/76
n = 3
Molecular formula = (Empirical formula)n
= (C3H8O2)3 = C9H24O6
The molecular formula is C9H24O6
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given 3.5M and 10.5ml of zn(oh)2 find the molarity of nitric acid given 15.0 ml of nitric acid
10.5 milliliters of 3.5 M zinc hydroxide react completely with 15.0 milliliters of 4.9 M nitric acid.
What is molarity?It is a unit of concentration equivalent to moles of solute per liter of solution.
Step 1: Write the balanced equation.Zn(OH)₂ + 2 HNO₃ ⇒ Zn(NO₃)₂ + 2 H₂O
Step 2: Calculate the reacting moles of Zn(OH)₂.10.5 mL of 3.5 M Zn(OH)₂ react.
0.0105 L × 3.5 mol/L = 0.037 mol
Step 3: Calculate the reacting moles of HNO₃.The molar ratio of Zn(OH)₂ to HNO₃ is 1:2.
0.037 mol Zn(OH)₂ × 2 mol HNO₃/1 mol Zn(OH)₂ = 0.074 mol HNO₃
Step 4: Calculate the molarity of HNO₃.[HNO₃] = 0.074 mol / 0.0150 L = 4.9 M
10.5 milliliters of 3.5 M zinc hydroxide react completely with 15.0 milliliters of 4.9 M nitric acid.
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how the various concentrations of acid will affect the amount of limestone that is dissolved from each jar.
The explanation of the how the various concentrations of acid will affect the amount of limestone has been given below.
Effects of acid rain on limestone:-
When an acid combines with a carbonate, it produces carbon dioxide as a gas and forms a salt that is soluble in the carbonate and acid's water.There are several gases in the atmosphere that can dissolve in precipitation such as rain and snow.Some may produce acids in rain water, such as carbonic acid, sulfuric acid, and nitric acid.Because the concentration is modest, the rain is not highly acidic, but it is acidic enough to react with the carbonates that make up limestone.Thus we discussed the affects of acid rain on limestones above.
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Which of the following is a chemical change?
A) Mixing chalk powder with sand
B) Melting of ice
C) Dissolving sugar in water
D) Cooking an egg
Answer:
cooking an egg
Explanation:
Hope it works
What is the pH and pOH of a 1.2 x 10 M HBr solution?
-log(1.2x10^-3) = 2.92 = pH
14 - 2.92 = 11.08 = pOH
socratic
studycom
what is a chemical germicides that has been formulated for use on the skin and is registered and regulated by the food and drug administration? milady barbering
Antiseptics is a chemical germicides that has been formulated for use on the skin and is registered and regulated by the food and drug administration.
Chemical germicidesA chemical or chemical combination used to eradicate microorganisms. Any procedure that removes and/or kills microorganisms is referred to as decontamination. The same phrase is also used to remove or neutralize radioactive materials, toxic compounds.A germicide is a substance that may eliminate microorganisms, particularly harmful ones (sometimes known as "germs"). Antiseptics and disinfectants are both considered germicides. Disinfectants are antimicrobials solely administered to inanimate items, whereas antiseptics are germicides applied to live tissue and skin.Learn more about organism here:
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Calculate the volume in milliliters of a M nickel(II) chloride solution that contains of nickel(II) chloride . Round your answer to significant digits.
190 milliliters is the volume of a 0.92M nickel(II) chloride solution that contains 175 mmol of nickel(II) chloride (NiCI₂).
What is Molarity ?Molarity (M) is defined as the number of moles of solute dissolved in 1L of solution. Molarity is also known as Molar Concentration. The S.I unit of Molarity is molar (M) or mol/L.
Molarity = [tex]\frac{\text{Number of moles}}{\text{Volume of solution (in L)}}[/tex]
Moles of nickel(II) chloride = 175 mmol
Molarity of the nickel(II) chloride = 0.92 M
Convert mmol into mol
1 milimol = 0.001 mol
175 mmol = 0.175 mol
Now put the value in above formula to find the volume of solution
Molarity = [tex]\frac{\text{Number of moles}}{\text{Volume of solution (in L)}}[/tex]
[tex]0.92\ M = \frac{0.175\ mol}{\text{Volume of solution}}[/tex]
Volume of solution = [tex]\frac{0.175\ mol}{0.92\ M}[/tex]
Volume of solution = 0.1902 L
Convert L into mL
1 L = 1000 mL
0.1902 L = 0.1902 × 1000 mL
= 190.2 mL
≈ 190 mL
Thus from the above conclusion we can say that 190 milliliters is the volume of a 0.92M nickel(II) chloride solution that contains 175 mmol of nickel(II) chloride (NiCI₂).
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Disclaimer: The question was given incomplete on the portal. Here is the complete question.
Question: Calculate the volume in milliliters of a 0.92M nickel(II) chloride solution that contains 175 mmol of nickel(II) chloride (NiCI₂). Round your answer to significant digits.
1. If 2000 L of hydrogen gas at a pressure of 90.0 kPa is compressed into a cylinder with a volume of 100 L while keeping the temperature constant, what pressure will the gas exert
in the cylinder?
Answer:
1800 pascal
Explanation:
p1v1 = p2v2
p1v1/v2 = p2
90 * 2000 / 100 = p2 = 1800 pascal
If a person is spending 10 lakh rupees per second how many years will take to spend one mole rupees
Answer:
A person spends Rs. 10,000 per second.
In one year, he will spend = Rs. (10,000 x 3600 x 24×365) = Rs. 3.1536 x 10^11
1 mole rupees = Rs. 6.022 x 10^23
So it will take approximately 1.91 x 1012 years to spend 1 mole rupees.
Explanation:
ヾ(＾-＾)ノ
What is the minimum volume of 5.50 M HCl necessary to neutralize completely the hydroxide in 718.0 mL of 0.183 M NaOH
The volume of HCl required is 23.89 mL
Calculation of volume:
The reaction:
[tex]HCl + NaOH \rightarrow NaCl + H_2O[/tex]
As HCl and NaOH react in 1 : 1 ratio.
Volume of NaOH= 718 mL
Concentration= 0.183M
Volume of HCl= ?
Concentration= 5.50M
Using the dilution formula:
[tex]M_1\times V_1(NaOH)= M_2\times V_2(HCl)[/tex]
[tex]0.183\times 718= 5.50 \times V_2\\V_2=\frac{131.394}{5.50} \\V_2 = 23.89 \,mL[/tex]
Therefore,
Volume of HCl required will be 23.89 mL.
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A 2.65 g sample of a salmon colored poweder contains 0.70 g of chromium, 0.65 g of sulfur, and 1.30 g of oxygen. The molar mass is 392.2. What is the formula of the compound
The formula of the compound is [tex]$\mathrm{Cr}_{2} \mathrm{~S}_{3} \mathrm{O}_{12}$[/tex]
Given
Salmon colored powder = 2.65 g
Chromium = 0.70 g
Sulfur = 0.65 g
Oxygen = 1.30 g
Molar mass = 392.2
FormulaMolar mass = gram / moles
Molecular formulaA chemical equation that specifies how many atoms of each element there are in each substance's molecules.The simplest whole-number ratio of the various atoms in a compound is represented by an empirical formula. The precise number of various atom types present in a compound's molecule is indicated by the molecular formula.Molar mass of chromium
= 0.70 / 0.0135
= 52
Molar mass of salmon
= 0.65 / 0.0203
= 32.06
Molar mass of oxygen
= 1.30 / 0.0813
= 16
Molecular formula = 392.2 / (Cr + 3 S + 12 O)
= 392.2 / (52.00 + (3 x 32.06 + 12 x 16.00) ≈ 1
So, The formula of the compound is [tex]$\mathrm{Cr}_{2} \mathrm{~S}_{3} \mathrm{O}_{12}$[/tex]
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A slow reaction speeds up when a chemical is added.
When the reaction is complete, it is found that the
added chemical has not changed in any way. Using
the collision theory, explain this phenomenom.
The collision theory explains this outcome since when the reaction is complete reactant particles can not interact and therefore the reaction does not occur.
What is the collision theory?The collision theory is a well sustained theory used in chemistry that states reactions are caused by the collision of particles that form their molecules.
This theory (collision theory) may result very useful to explain the rate of change in a given chemical reaction.
In conclusion, the collision theory explains this outcome since when the reaction is complete reactant particles can not interact and therefore the reaction does not occur.
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The process by which liquid metals turns into tiny solid particles at the phase boundary temperature is called:
What is Solidification?
The process by which liquid metals turn into tiny solid particles at the phase boundary temperature is known as solidification or freezing.
How does solidification occur?
Solidification occurs when a liquid's temperature is reduced below its freezing point. Although the freezing point and melting point of the majority of materials are the same temperatures, this is not always the case and the words freezing point and melting point are not synonymous.
When a liquid turns into a solid, the process is always exothermic, which means heat is released.
Based on casting technology, solidification is a key component of several other processes, such as crystal growth, welding, surface alloying, the manufacturing of ingots, and the purification and refinement of raw materials. It is a crucial step in the technology of metals, as well as ceramics and polymers.
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according to kinetic molecular theory, which of the following would not be considered an ideal gas
Answer:
A gas at very low volumes, when gas particles are very close together
A gas at very low temperatures, when gas particles have very little kinetic energy
A gas with highly polar molecules that have very strong inter-molecular forces
Explanation:
The Kinetic Molecular Theory:
particles in a gas are in constant, random motioncombined volume of the particles is negligibleparticles exert no forces on one anotherany collisions between the particles are completely elasticaverage kinetic energy of the particles is proportional to the temperature in kelvinsRM / NV / NF / EC / ET
Although none of the assumptions provided in the molecular theory of gases are strictly correct, they are fair enough for modeling some systems. It is an idealized approach of real systems. The fundamental presumptions are nearly identical to those of an ideal gas.
The most logical of the hypotheses is that of elastic collisions. Since gas molecules are treated as perfectly hard spheres in Newton's equations and elastic collisions, there is no energy lost in compressing the gas molecules during a collision.
For bulk, light gases at moderate temperatures and low to moderate pressures, it is acceptable to assume that there is an attractive force between the gas and the container wall. Since the walls of the containers only account for a minor portion of collisions in macroscopic quantities, they can typically be disregarded. Only until the gas's total density exceeds the kinetic energy do forces between its particles start to become significant. For light gases like He and straightforward diatomic gases, the kinetic energy of the gas molecules far outweighs the intramolecular interactions at normal temperatures.
But in a complete way of the KM theory being described:
The microscopic characteristics of atoms (or molecules) and their interactions, which result in observable macroscopic qualities, are described by the kinetic molecular theory of matter (such as pressure, volume, temperature). The idea may be used to explain why matter exists in distinct phases (solid, liquid, and gas), as well as how matter can transform between these phases.
The three states of matter are: As we transition from the solid to the gaseous phase, you'll notice that the distance between atoms or molecules widens.
According to the kinetic molecular theory of matter,
Particles that make up matter are continually moving.Every particle has energy, however the amount of energy changes with the temperature of the sample of matter. Thus, whether the material is in a solid, liquid, or gaseous form is determined. The least energetic molecules are those in the solid phase, whereas the most energetic particles are those in the gas phase.The average kinetic energy of the particles in a material may be calculated from its temperature.When the particles' energies are altered, the phase of the particles may vary.Matter atoms are separated by gaps. As a sample of matter transitions from the solid to the liquid and gas phases, the average amount of vacant space between molecules increases.Atoms and molecules interact by attraction forces, which intensify as the particles draw closer to one another. Intermolecular forces are the name for these pulling forces.How does kinetic molecular theory affect gases?According to the Kinetic Molecular Theory, gas particles collide in an elastic manner and are always in motion. Only absolute temperature directly affects a group of gas particle's average kinetic energy.
Part I of How the Kinetic-Molecular Theory Explains Gas Behavior.
If the volume is kept constant, the faster gas molecules collide with the container walls more frequently and more violently, raising the pressure according to Charles' law.
Answer:
See below
Explanation:
Gas at LOW PRESSURE or high temperature with little or no intermolecular forces would be closest to ideal gas behavour.
Which statement is true if the AHrxn of a reaction is positive?
∆H of a reaction is positive
Means the reaction is emitting energy in terms of product Hence the reaction is exothermicThe energy is given to the surroundingsExplain how the experimental molecular mass would have been affected (too high, too low or unchanged) if the mass of the flask had been measured with condensed vapor and residual water on the outside. Please support your answer.
If the flask already has water, your measure is going to be higher than expected and MW is going to be higher too.
At first sight, we need to assume 1 atm as atmospheric pressure, probably forgot to write down this value in the Lab. By doing this, we got all values to calculate the MW.
So, for trial 1:
MW = [0.36 g x (0.082 atm x L / K x mol) x 301 K] / (1 atm x 0.125 L) = 71.08 g/mol
Trial 2:
MW = [0.38 g x (0.082 atm x L / K x mol) x 301 K] / (1 atm x 0.125 L) = 75.53 g/mol
Average MW = 73.31 g/mol
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Which of the following statements is one
of the postulates in Dalton's atomic
theory?
a. All elements are composed of atoms.
b. Most elements are composed of atoms.
c. Some elements are composed of atoms.
d. Solid elements are composed of atoms.
Answer:
a. All elements are composed of atoms.
Explanation:
dalton's atomic theory says that Compounds are composed of atoms of more than 1 element. The relative number of atoms of each element in a given compound is always the same. Chemical reactions only involve the rearrangement of atoms. Atoms are not created or destroyed during chemical reactions.
How much heat is needed to vaporize 10.00 grams of water at 100.0°c? the latent heat of vaporization of water is 2,259 j/g. 22.59 j 1,000 j 2,269 j 22,590 j
The correct option is:
The latent heat of vaporization of water is given by option D. 22,590J
Latent heat of vaporization:
Latent heat of vaporization is energy required to change 1 kg of liquid to gas at atmospheric pressure at its boiling point.
Also, Latent heat is the energy released or absorbed during a phase change.
Energy released during phase change is Exothermic process.
Whereas energy absorbed during phase change is Endothermic process.
Q=mL
Q= Latent heat
m= mass= 10 g
L= Latent heat of vaporization= 2,259 J/g
Putting the values in the above equation:
Q=10*2259
Q=22590 L
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The. bond dissociation enthalpies of the H-H bond and the H-Cl bond are 435 kJ mol^-1 and 431 kJ mol^-1, respectively. The ΔHfO of HCL(g) is -92kJ mol^-1 . What is the bond dissociation enthalpy of the Cl-Cl bond?
The bond dissociation energy of the Cl - Cl bond is -958 kJ mol^-1.
What is the dissociation enthalpy?Given that;
H-H bond energy = 435 kJ mol^-1
H-Cl bond energy = 431 kJ mol^-1
ΔHfO of HCL(g) = -92kJ mol^-1
Bond dissociation enthalpy of the Cl-Cl bond = x
-92 = 435 + 431 + x
x = -92 - (435 + 431)
x = -958 kJ mol^-1
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What is the percent by mass of water in copper (II) sulfate pentahydrate (CuSO4 · 5H4O)? Type in your answer using one decimal place.
Percentage by mass of water in CuSO4.5H20 is 36.07% .
In this problem we have - copper(II) sulfate pentahydrate and it's molecular formula is (CuSO₄.5H₂O) .
There are 5 molecules of water are present.
Now we calculate it's molar mass-
We know that-
molar mass of Cu = 63.5u
Molar mass of SO₄ = 96 u
Molar mass of H₂O = 18 u
Now, molar mass of (CuSO₄.5H₂O) = 63.5 + 96 + 5 × 18
Now, molar mass of (CuSO₄.5H₂O) = 249.5u
And mass of water in CuSO₄.5H₂O = 90 u
now mass percentage of water = mass of water ÷ Total mass ×100
now mass percentage of water = 90 ÷ 249.5 × 100
now mass percentage of water = 36.07 %
So we find out mass percent by dividing given mass with total mass and then multiplying it with hundred and it came out to be 36.07 % .
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Answer:
36.1
Explanation:
A rock formed with 2,000 atoms of a radioactive parent element, but only contains 500 radioactive parent atoms today. If the half-life for the radioactive element is one million years, how old is the rock
Answer:
2 million years
Explanation:
500/2000 = 1/4, meaning the sample decayed to 1/4 of its original amount. From this, we can conclude that 2 half lives have passed.
In the problem, we are given one half life is 1 million years. Multiplying this by 2, we get that 2 half lives is 2 million years.
"Deka" is a decimal unit prefix in the metric system, denoting a factor of
Select one:
a. 10
b. 100
c. 1,000
d. 10,000
Answer:
10
Explanation:
Deca or deka is a decimal unit prefix in the metric system denoting a factor of ten. For example, DECAGON is a 10-sided polygon (10-gon).
What is 1 atmospheric pressure?
Answer:
101325 pascal
Explanation:
i dont cap
Answer:
See below
Explanation:
1 atmosphere = 101 325 Pascals = 760 mm Hg = 14.6959 psi
Which chemical formula corresponds to this structural formula? h6c6h6h2 c14h6 c6h6 c2h6o
C₂H₆O is referred to the chemical formula corresponds to this structural formula and is denoted as option D.
What is Chemical formula?This contains information about the chemical proportion of atoms present in a molecule.
In this scenario, there are two carbon atoms, six hydrogen atoms and one oxygen atom which can be written as C₂H₆O. This is therefore the most appropriate choice in this scenario.
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Answer: D.) C6H14
Explanation: i hope this helps (this is for another question you might have tho) :)
Please help I need an answer , URGENTLY !
Answer:
Aluminium metal reacts vigorously with all the halogens to form aluminium halides. So it reacts with chlorine, bromine, and iodine.
A certain hydrocarbon has a chemical composition of 79.85% of carbon and 20.15% of hydrogen. The molar mass is 60.16 g/mol. What is the molecular formula for this compound
The molecular formula for the compound is [tex]C_{4} H_{8}[/tex] .
Given:% of C = 79.85%
% of H = 20.15%
Let the mass of the compound be 100g, then
Mass of C = 70.85 g
Mass of H = 20.15 g
Molar mass = 60.15 g/mol
Moles of Carbon = [tex]\frac{79.85}{12.01 g/mol}[/tex]
= [tex]6.64 mol[/tex]
Moles of Hydrogen = [tex]\frac{20.15}{1.00794 g/mol}[/tex]
= [tex]19.99 mol[/tex]
And we divide both sides by the lower quantity;
[tex]C_{\frac{6.64 mol}{6.64 mol} } H_{\frac{19.99 mol}{6.64 mol} }[/tex] ≅ CH₂
And [tex](empirical formula)_{n} = molecular formula[/tex]
60.15 g/mol = n × ( 12.01 + 2 × 1.00794)
n = 4
Therefore, the molecular formula for the compound is [tex]C_{4} H_{8}[/tex] .
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A 0.674m cobalt (ii) chloride (cocl2) solution is prepared with a total volume of 0.0750l. the molecular weight of cocl2 is 128.9 g/mol. what mass of cocl2 in grams is needed for this solution?
The mass of CoCl₂ is 6.515 g.
Calculation:
Given,
Molarity of the solute (CoCl₂) = 0.674 M
Volume of solution = 0.0750 L
Molecular weight of solute (CoCl₂) = 128.9 g/mol
Molarity formula is used to solve this question.
Molarity is defined as the number of moles of solute per liter of solution.
[tex]Molarity = \frac{number of moles }{volume (in L)}[/tex] .......(i)
We know that,
[tex]number of moles = \frac{weight of given solute }{molecular mass if the solute}[/tex] ........(ii)
Put the above values in equation (i)
[tex]0.674 = \frac{number of moles}{0.0750}[/tex]
[tex]number of moles = 0.674 (0.0750)[/tex]
[tex]number of moles = 0.05055[/tex]
Put the number of moles in equation (ii)
[tex]0.05055 = \frac{weight of given solute}{128.9}[/tex]
[tex]weight of given solute = 0.05055 (128.9)[/tex]
[tex]weight of given solute = 6.515 g[/tex]
Therefore, 6.515 g of CoCl₂ is needed.
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What is the [H+] if the pH of a
solution is 11.3?
[H+] = [? ] × 10^[?]]
Answer:
5.01 x 10^-12
Explanation:
Formula [H+]=10^-ph 》》 10^-11.2
-Hope this helps!!